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PCB export at the lower Ottawa River (Maumee River AOC): A pre- and post-dredging analysis of sediment, passive samplers, aquatic invertebrates, and riparian spiders
Citation:
Otter, R., D. Walters, Jim Lazorchak, K. Fritz, AND M. Mills. PCB export at the lower Ottawa River (Maumee River AOC): A pre- and post-dredging analysis of sediment, passive samplers, aquatic invertebrates, and riparian spiders. To be Presented at SETAC North American 39th Annual Meeting, Sacramento, CA, November 04 - 08, 2018.
Impact/Purpose:
Prior to dredging, we designed a multi-metric study to assess contaminant fate and transport, ecosystem response, and recovery using a multiple lines of evidence approach. We measured PCB concentrations in surface sediment, passive samplers deployed in the water column, aquatic invertebrates, and spiders from 2009-2013 & 2015.
Description:
Environmental dredging at select site locations was performed within the lower Ottawa River, a portion of the Maumee River Area of Concern (Ohio, USA), in 2010 to remediate sediments contaminated with PCBs, PAHs, and lead. Prior to dredging, we designed a multi-metric study to assess contaminant fate and transport, ecosystem response, and recovery using a multiple lines of evidence approach. We measured PCB concentrations in surface sediment, passive samplers deployed in the water column, aquatic invertebrates, and spiders from 2009-2013 & 2015. Site-specific PCB concentrations were significantly and positively correlated among all metrics across all years except for sediment. Sediment concentrations at remediated and non-remediated sites were highly variable throughout the study period and were unreliable indicators of PCB concentrations in biota. PCB concentrations in aquatic invertebrates were highly correlated with concentrations measured in passive samplers, and in turn, were strongly predictive of concentrations in riparian spiders that are specialized predators of adult aquatic insects. All of these measures of PCB uptake, accumulation, and trophic transfer declined by 2015, indicating that the dredging remedy was successful in reducing PCBs concentrations in biota within the Area of Concern.